The present invention relates to a prosthetic graft and a method and apparatus for placing the graft within a body passage. In its more particular aspects, the invention is concerned with a resilient tubular graft which may be reduced in diameter for delivery and then expanded into place. The invention is especially concerned with such a graft which may be deployed within the thoracic aorta, the abdominal aorta, or the femoral artery, via a groin incision.
The prior art teaches expansible tubular grafts for use in body passages. For example, U.S. Pat. No. 4,655,771 discloses such a graft which may be elongated for delivery and then expanded into place. With the device of that patent, the ends of the graft are held within tubular fixtures which are used to impart elongation to the graft to reduce its diameter during delivery. Once the graft is in place, these fixtures are removed to release the graft for expansion. The employment of the fixtures necessarily adds to the-bulk and complexity of the mechanism and limits its use.
Another example of an expansible intraluminal graft is found in U.S. Pat. No. 4,776,337. The device of that patent is fabricated of a malleable material which is delivered in a reduced diameter condition and, once in place, expanded by an angioplasty balloon to dilate and expand the lumen of a blood vessel.
The prior art also teaches expansible devices for vessel dilation embodying braided cylinders of an adjustable axial length structured such that a reduction in the length increases the radial size of the device. U.S. Pat. No. 4,572,186 shows such a device.
It is also known to provide sheaths which may be placed in vessels to facilitate the passage of other instruments or catheters therethrough. U.S. Pat. Nos. 4,493,711 and 4,798,193 teach such devices.
The graft of the present invention is resilient and of a tubular configuration adapted to assume a foreshortened enlarged diameter condition upon relaxation and, upon being elongated, assume a reduced diameter condition. The mechanism for delivery of the graft comprises an elongate placement means which extends longitudinally of the graft to carry the graft through a body passage and facilitate its placement. Flexible lines secure opposite ends of the graft to the elongate placement means. The lines are movable to selectively elongate the graft for delivery, or expand the graft for placement. A retractable sheath may be provided to shield the mechanism and graft during the delivery process.
The method of the invention comprises the steps of securing opposite ends of the graft to a placement member with flexible lines, moving the lines to elongate the graft, passing the placement member through a body passage with the graft carried thereby in a reduced diameter elongated condition, and positioning the graft and releasing the lines at the desired location. In the preferred embodiment the lines are also extended around the graft to subject it to radial compression simultaneously with its elongation.
A principal object of the invention is to provide an improved graft and system and method for its delivery and placement which enables the graft to be delivered through elongate body passages.
Another object of the invention is to provide an improved expansible tubular graft which may be fabricated with fluid permeable, or impermeable, walls.
Still another object is to provide such a graft which is biocompatible with the body and has means to securely anchor it in place.
A further object is to provide such a graft which may be securely placed with a main artery without blocking branch arteries, even where there is not a substantial length of healthy artery between the aneurysm being treated and the branch arteries.
Yet another more general object of the invention is to provide an improved apparatus and method for intraluminal delivery of a graft to a select remote area within a body passage, without need to surgically access the area.
Yet a further object of the invention is to provide an apparatus and method for the intraluminal placement of a graft within a body passage which may be carefully controlled to provide precise placement of the graft and repeatedly adjusted.
Still another object related to the latter object is to provide such an apparatus and method wherein the graft can be precisely located and fully expanded before its release from the delivery system.